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` A118 7, 1956 G. M. DE JARLAls Re 24,192

' MOTOR COOLING SYSTEMS Original Filed May 15' 1946 2 sheets-sheer 1ffy@ IN V EN TOR.

ug- 7, 1956 G. M. DE JARLAls Re. 24,192

MOTOR COOLING SYSTEMS Original Filed May l5, 1946 2 Sheets-Sheet 2United States Patent Oce' asignments, to Whirlpool-Seeger Corporation,St.` Joseph, Mich., a corporation of Delaware No. 2,459,311, datedJanuary 18, 1949, Serial No. 669,756, May 15, 1946. Application forrelllle October 30, 1952, Serial No. 317,851

Matter enclosed in heavy brackets appears in the patent but forms nopart of this reissue specifin; matter printed in italics indicates theadditions made by reissue.

lThe present invention relates to motor cooling systems, and isparticularly concerned with an improved cooling system for cooling themotors of refrigeration systems of the type employing a motorcompressor.

The present invention 'relates to an improved system over that coveredby the United States patent to J ames H. Dennedy No. 1,960,576, issuedMay 29, 1934, on a refrigeration system.

One of the objects of the invention is the provision of an improvedmotor cooling system which is adapted td provide the most eicientcooling for the motor and compresser of a refrigeration system.

Another object of the invention is the provision of an improved motorcooling system for refrigeration apparatus by means of which the coolingtins on the compressor housing may be eliminated, and the noise level ofthe apparatus substantially reduced.

Another object of the invention is the provision of an improvedrefrigeration system with provision for motor and compressor cooling,that is also adapted to produce efficient oil separation so that oil iskept out of the low side of the system and the efciency of the system isnot reduced by circulating large amounts of oil through the evaporator.

Another object of the invention is the provision of an improved motorcompressor construction and motor cooling apparatus in which the ,motorand compressor have separate housings but the usual housing enclosingthe assembly is not required and, therefore, the cost of the motorcompressor assembly may be substantially reduced.

Still another object of the invention is the provision of an improvedcooling system for the motors of refrigeration apparatus which isadapted to utilize effectively the cooling arrangements such as thecondenser tubes which are provided for this purpose, and in which thecooling effect conforms very closely to the cooling which is required.

Another object of the invention is the provision of an improvedrefrigeration system which is ecient and in which the motor isadequately cooled and oil returned to the oil reservoir in the motorhousing so that the oil which is circulated through the lo'w side of thesystem is reduced to a minimum.

Another object of the invention is the provision of'an improvedrefrigeration system which is simple, efficient, sturdy, adapted to bemanufactured at a low cost, and capable of being used for a long periodof time without necessity for repair or replacement or other servicing.

Other objects and advantages of the invention will be apparent from thefollowing description and the accompanying drawings, inwhich similarcharacters of reference indicate similar parts throughout the severalviews.

Referring to the drawings, of which there are two sheets,

Re. 24,192 lReissued Aug. 7, 1956 Fig. 1 is a diagrammatic elevationalview of the refrigeration system; l l

Fig. 2 is a fragmentary rear elevational view of the cabinet showing arear view of the removable refrigeration unit; and

Fig. 3 is a side elevational view of the removable refrigerationapparatus shown Ain partial section and shown in a fragmentary sectionalview of the cabinet.

Referring to Fig. 1, the present refrigeration system preferablyincludes a motor 10 and a compressor l-l driven by the motor, and acondenser 12 which utilizes a pair of condenser sections 13 and 14 forreducing the vaporized refrigerant to liquid and for cooling the motor.

In the diagrammatic system of Fig. l, 15 indicates the evaporator, 16the 'oatvalve chamber, and the course of Ythe refrigerant through thevsystem is 'as follows: The

outlet from the motor compressor ll is connected by conduit 17 to theinlet part of the condenser section 13, which may comprise one or moreof the tubes which are thermally connected to the same ns 18 as areconnected to the main condenser section 14.

The outlet end of the tubes of the condenser section 13 is connected byconduit 19 to the interior of the motor housing 10, preferably atitsupper end. Another conduit 20 leads from the upper end of the motorhousing l0 to the inlet end of the tubes forming the condenser'seetion14, and the outlet end of these tubes is connected by a conduit 21 tothe oat valve chamber 16.

The discharge opening from the oat valve chamber 16 is connected by aconduit 22 to the refrigerant distributing conduit 23 of an evaporator15, and the vapor headers 24 of the evaporator are connected by aconduit 25 to the inlet of the motor compressor 11.

Referring to Fig. 2, this is a rear elevational view of the actualrefrigeration apparatus unit of the type 'adapted to be mounted in thebackl of a cabinet in such manner that the motor and compressor arehoused partly in the rear wall and partly outside of the cabinet shell.The same numerals have been applied to the parts of this drawing, butthe structure is shown in greater detail, and it will be noted that themotor 10 and compressor 11 do not require an additional assembly housingenclosing the separate motor and compressor housing.

-The motor housing is here indicated by the numeral 26 and it is shownin connection with the motor shaft 427, motor 28, shaft bearing 29,stator 30 and windings 3l. The housing 26 of the motor 10 ishermetically sealed and has a chamber or space 32 at its upper endadjacent the inlet from the conduit 19 and the outlet to the conduit 20.

The operation ofthe system is as follows: Refrigerant vis withdrawn fromthe evaporator 15 directly into the compressor cylinder 11 through thevapor conduit 25. This permits operation with a minimum heating of thesuction gas, as contrasted with the systems of the prior art in whichthe suction conduitv may lead into an auxiliary housing of thecompressor or motor, which housing itself is heated by being in metalliccontact with the compressor and motor.

Heating the suction gas before entering the compressor would reduce thedensity of the gas, which in turn would reduce the capacity of thecompressor, and it is desirable to avoid such heating because it wouldthus reduce the efficiency of the compressor. Therefore, theintroduction of refrigerant vapor directly into the cylinder of thecompressor permits the compressor to operate more efliciently than itwould if the'suction gas had been heated and had thus had its densityreduced.

The compressed and, therefore, heated vapor is conducted directly outyof the compressor 11 by the conduit 17 in order to carry away fromthecompressor and motor,

at the earliest opportunity, the heat which has been generated by thecompressor. If this heated and compressed gas from the compressor outletwere brought mto contact with auxiliary housings of metal which are alsocon- `nected to the motor, much of this heat might be transmitted byconduction to the motor whereas the present system provides for thecarrying away of the heat of the compressed vapor at once.

The discharge vapor contains superheated refrigerant gas and sconsiderable amount of lubricating oil, the latter being in a mist orvapor condition. The discharge vapor is at a relatively high temperatureas compared with the temperature of the system.

This discharge vapor from the compressor is conducted by conduit l1 tothe inlet portion 13 of the condenser through which it is passed andpartially cooled and condensed. In this portion of the condenser thesuperheat of the refrigerant gas is removed, a portion of therefrigerant gas is condensed to a liquid and is mixed with thelubricating oil which is also now reduced to a liquid condition.

The preliminary cooling of the discharge vapor from the compressor isaccomplished under the most etlicient conditions, because it takes placeat the highest possible temperture difference, that is, the superheatedvapor temperature of approximately 250 F., as compared with the ambientair temperature assumed to be 110 F.

Thus the cooling may be accomplished with the least possible amount ofcondenser surface From the condenser section 13 the refrigerant gas isconducted by conduit 19 into the motor housing A26. The conduit 19carries refrigerant gas at saturation temperature and drops of theliquid oil-refrigerant mixture, the refrigerant having been onlypartially liquefied.

Emerging from the conduit 19 into the motor housing space 32 thevelocity of the gas and entrained liquid is greatly reduced because ofthe enlarged cross-sectional area of the stream in the space 32. Thisreduction in velocity causes the liquid to drop and the oil refrigerantmixture contacts'and cools the motor. The oil runs down through thewindings to the oil sump. Therefore, no separate cooling or oilseparation system is required As described in the prior patent to JamesH. Dennedy, to which reference is made on page l, a suitable conduit Thesaturated vapor-oil refrigerant mixture enters the motor housing and isagain heated so that on leaving the housing the temperature may beapproximately 200 F. or 50' F. superheat.

At low ambient temperatures, such as 80 F.' to 70 F., there is asomewhat larger amount of refrigerant in the oil which cools thecompressor cylinder. The resulting discharged vapor carries lesssuperheat than is encoun- -tered in the case of adverse conditions. Onpassing through the housing therefrigerant picks up very littlesuperheat (4 F. to 8 F.).

Thus where a relatively large cooling effect is required, it is providedby this system and where a relatively small cooling effect is requiredthe system conforms to this requirement.

It will thus be observed that I have invented an improved cooling systemadapted to cool the motor and compressor of a refrigeration apparatusvery eciently, while separating the oil and keeping the oil out of theevaporator, thus increasing the etiiciency of the entire refrigerationsystem.

The present motor cooling systetm is very ellcient in regard tocondenser area as it operates at a maximum temperature diterence. Noseparate oil coolings or oil separators are required, and the auxiliarymotor and comy pressor chambers may be eliminated.

The present system eliminates the necessity for cooling tins on thecompressor housing and thus effects a reduction ofthe noise level, assuch fins may tend to vibrate and cause a hum or an increased noiselevel. The coolv ing elfect produced by my system also conforms quite`closely to the cooling which is required under different ambienttemperature conditions.

While I have illustrated a preferred embodiment of my invention, manymodifications may be made without departing from the spirit of theinvention, and I do not wish to be limited to the precise details ofconstruction (not shown) is provided for conducting oil from the oilsump at the base of the motor housing back to the compressor inlet.

The liquid refrigerant partially condensed in the condenser section 13is vaporized by contact with the heated motor parts, cooling the motorvery eectively by utilizing heat of the motor to evaporate the liquidrefrigerant.

The refrigerant vapor fromthe space 32 of the motor housing, containingpractically no oil, is then conducted from the housing through theconduit 20 to the main or second section 14 of the of the condenser 12.Here the refrigerant is condensed and its llow being regulated by thefloat valve chamber in the chamber 16 the refrigerant again enters theevaporator 15.

yVarious types of evaporators may be employed, the one selected forillustration having a refrigerant distributing conduit at the bottom, amultiplicity of conduits extending upwardly on both sides between sheetsof metal and headers 24 at the top. The suction pipe 25 is connected tothe headers 24.

It has been found that where a relatively large cooling eectis requiredthe present system conform to the requirement, and where a relativelysmall cooling eEect is required the system also conforms to the coolingrequirement under theseconditions.` For example; if the sysset forth,but desire to avail myself of all changes within the scope of theappended claims. I

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent'of the United States, is: l

l. The method of refrigeration which comprises with'- drawing vapor froman evaporator directly into a compressor located outside of a motorhousing, compressing the vaporand discharging the superheated andcompressed vapor directly from the compressor into a precoolingcondenser, partially condensing the vapor and consolidating the oilentrained therewith into droplets in said condenser and conducting thepartially condensed vapor and oil from the condenser into an upper partof the housing of a motor driving said compressor and having a housingseparate from vsaid compressor, causing the condensed liquid refrigerantand oil to run down in the motor housing to cool the motor parts, therefrigerant again evaporating in this cooling operation, an'd the oilbeing separated and collected in an oil sump, land discharging the vaporsubstantially without oil from the top of the motor housing into a maincondenser, where it is cooled and liquefied for use in the evaporator.

2. The method of refrigeration which comprises withdrawing vapor from anevaporator directly into a compressor located outside of a motorhousing, compressing the vapor and discharging the superheated andcompressed vapor directly from the compressor into a preliminary coolingcondenser, partially condensing the vapor and consolidating the oilentrained therewith into droplets in said condenser and conducting thepartially condensed vapor and oil from the condenser into an upper partof the housing of a motor driving said compressor and having a housingseparate from said comthe refrigerant again evaporating in this coolingoperation, and the oil being separated and collected in an oil sump, anddischarging the vapor substantially without oil from the top of themotor housing into a main condenser, where it is cooled and liqueed foruse in the evaporator, and cooling the external parts of the. motorhousing and the compressor housing and removing the heat radiatedtherefrom by passing a current of air upward from the said condensers.

3. In a refrigeration system, a motor compressor assembly comprising amotor having a separate housing and a compressor having a separatehousing, these housings being located adjacent each other, and the motormotor housing, and said preliminary condenser-having a predeterminedheat exchange area to condense partially the refrigerant vapor andconsolidate the entrained oil into droplets, the partially condensedrefrigerant and oil running down on the motor parts inside the motorhousing, and the partially condensed vapor effecting a cooling of saidmotor parts with a resultant` revaporization of the refrigerant in themotor housing, the oil collecting in a sump in the lower part of themotor housing to separate the oil from the refrigerant, a main condenserhaving a predetermined heat exchange area-to cool and liquefy therefrigerant vapor received from the motor housing, the said motorhousing having another conduit connecting its upper part with said maincondenser, and conduit means connecting said main condenser with theevaporator. t

4. In a refrigeration' system, a motor compressor assembly comprising amotor having a separate housing and acompressor having a separatehousing, .these housings being located adjacent each other, and themotor having a shaft extending into the compressor, an evaporator havingits suction side directly connected to the inlet of said compressor, apreliminary cooling condenser having its inlet connected directly to theoutlet of the compressor, whereby the superheated and compressed gas iscarried away from the compressor without said gas passing through themotor housing, the outlet of said preliminary ccnls'er being connectedtothe top of the motor housing, and said preliminary condenser having apredetermined heat exchange area to condense partially the refrigerantvapor and consolidate the entrained oil into droplets, the partiallycondensed refrigerant and oil running down on the motor parts inside themotor housipg, and the partially condensed vapor effecting a cooling ofsaid motor parts with a resultant revaporization of the refrigerant inthe motor housing, the oil collecting in a sump in the lower part of themotor housing to separate the oil from the refrigerant, a main condenserhaving a predetermined heat exchange area to cool and liquefy therefrigerant vapor received from the motor housing, the said motorhousing having another conduit connecting vits upper part with said maincondenser, and conduit means connecting said main condenser with theevaporator, the amount of cooling effect of said system on the motor andcompressor being determined by the ambient temperature in which thesystem operates so that there is a greater cooling eect, as required,when the system is operating in a higher ambient temperature.

5. In a refrigeration system, a motor compressor asfsembly comprising `a`motor having a separate housing and a compressor having a separatehousing, these housings being located adjacent each other, and the motorhaving a shaft extending into the compressor, an evaporator having itssuction side directly connected to the inlet of said compressor,-apreliminary cooling condenser having its inlet connected directly to theoutlet of the compressor, whereby Ithe superheated and compressed gas iscarried away from the compressor without said gas passing through ythemotor housing, the outlet of said preliminary condenser being connectedto the top of the motor housing, and. said preliminary condenser havinga predetermined heat exchange area to condense partially the refrigerantvapor and consolidate the entrained oil into droplets, the partiallycondensed refrigerant and oil running down on the motor parts inside themotor housing, and the partially condensed vapor effecting a cooling ofsaid motor parts with a resultant revaporization of the refrigerant inthe motor housing, the oil collecting in a sump in the lower part of themotor housing to separate the oil from the refrigerant, a main condenserhaving a predetermined heat exchange area to cool and liquefy therefrigerant vapor received from the motor housing, the said motorhousing having another conduit connecting its upper part with said maincondenser, and conduit means connecting said main condenser with theevaporator, the said main condenser section including a lheat exchangearea many times that of the preliminary condenser, and the saidcondensers being located below the motor and compressor in the stream ofair-passing upward about the motor and compressor.

6. In a refrigeration system, a motor compressor assembly comprising amotor having a separatehousing and a compressor having a separatehousing, these housings being located adiacent each other, and forming asingle casing arranged to receive refrigerant and having a lubricantreservoir, and the motor having a shaft extending into the compressor,forming a compressor motor combination unit, with the motor above thecompressor, said unit having a channel medium extending into said`lubricant reservoir to allow the working parts of said compressor to belubricated, a charge of refrigerant and oil in said system, anevaporator having its suction side directly connected lto the inlet ofsaid compressor, a preliminary cooling condenser having its inletconnected directly to the outlet of the compressor, whereby thesuperheated and compressed gas is carried away from the compressorwithout said gas passing through the motor housing, the outlet of saidpreliminary condenser being connected to the top of the motor housing,and

said preliminary condenser having a predetermined heat exchange area tocondense partially the refrigerant vapor and consolidate the entrainedoil into droplets, the partially condensed refrigerant and oil runningdown on the motor parts inside the motor housing, thereby lubricatingthe motor, and the partially condensed vapor eecting a cooling of saidmotor parts with a resultant revaporization of the refrigerant in themotor housing, the oil collecting in a sump in the lower part of themotor housing to separate the oil from the refrigerant, a main condenserhaving a predetermined heat exchange area to cool and liquefy therefrigerant vapor received from the motor housing, the said motorhousing having another conduit connecting its upper part with said maincondenser, and conduit means connecting said main condenser with tlieevaporator, said preliminary cooling condenser comprising a separatecoil arranged exteriorly of the casing, and the gas exerting a pressureon the oil in the reservoir characterizing a forced lubrication of thecompressor parts through said channel medium.

7. In a refrigeration system, a motor compressor assembly comprising amotor having a separate housing and a compressor havingv a separatehousing, these housings being located adiacent each other, and forming acasing arranged to receive refrigerant and having a lubricant reservoir,and the motor having a shaft extending. into the compressor, forming acompressor motor combination unit, with the motor above the compressor,a charge of refrigerant and oil in said system, an evaporator having itssuction side directly connected to the inlet of said compressor, saidunit pumping refrigerant from said evaporator to compress therefrigerant, a preliminary cooling condenser having its inlet connecteddirectly to.

the outlet lof the compressor, whereby the superheated and compressedgas is carried away from the compressor without said gas passing throughthe motor housing, the outlet o f said preliminary condenser beingconnected to the top of the motor housing, and said preliminarycondenser having a predetermined heat exchange area to condensepartially the refrigerant vapor and consolidate the entrained oil intodroplets, the partially condensed refrigerant and oil running down onthe motor parts in side the motor housing, thereby lubricating themotor, and the partially condensed vapor eecting a cooling of said motorparts with a resultant revaporization of the refrigerant in the motorhousing, the oil collecting in a sump in the lower part of the motorhousing to separate the oil from the refrigerant, a main condenserhaving a predetermined heat exchange area to cool and liquefy therefrigerant vapor received from the motor housing, the said motorhousing having another conduit connecting its upper part with said maincondenser, and conduit means connecting said main condenser with theevaporator, said preliminary cooling condenser comprising a separatecoil arranged exteriorly of the casing.

8. In a refrigeration system, a motor compressor assembly comprising amotor having a separate housing and a compressor having a separatehousing, these housings being located adfacent each other, and forming at casing arranged to receive refrigerant and having d lubri- `ca'ntreservoir, and the motor having a shaft extending into the compressor,forming a compressor motor combination unit, with the motor above thecompressor, an evaporator having its suction side directly connected tothe inlet of said compressor, a preliminary-cooling condenser having itsinlet connected directly to the outlet of the compressor, whereby thesuperheated and compressed gas is carried away from the compressorwithout said gas passing through the motor housing, the outlet of saidpreliminary condenser being connected to the top of the motor housing,and said preliminary condenser having a predetermined heat exchange areato condense partially the refrigerant vapor and consolidate theentrained oil into droplets, the partially condensed refrigerant and oilrunning down on the motor parts inside the motor housing, therebylubricating the motor, and the partially condensed vapor eecting acoolingtof said motor parts with a resultant revaporization of therefrigerant in the motor housing, the o il collecting in a-sump meansconnecting said main condenser with the evaporator, said preliminarycooling condenser comprising a separate coil arranged exteriorly of thecasing, the amount of cooling eect of said system on the motor andcompress'or being determined by the ambient temperature in which thesystem operates so that there is a greater cooling eect, as required,when the system is operating in a higher ambient temperature.'

9. The method of refrigeration which comprises withdrawing vapor from anevaporator directly into a compressor located outside of--a motorhousing, compressing the vapor and discharging the superheatedandcompressed vapor directly from the compressor into a preliminarycooling`condenser, cooling lthe superheated and compressed vapor andoil. to a temperature below the temperature of the motor parts, in saidcondenser, par tially condensing .the vapor and consolidating the oilentrained therewith into droplets in said condenser and conducting thepartially condensed vapor and oil from the condenser into an upper partof the housing of a motor driving said compressor and having a housingseparate from said compressor, causing the condensed liquid refrigerantand oil to run down in the motor housto cool the motor parts, therefrigerant again evaporating in this cooling operation, and the oilbeing separated and collected in an oil sump, and discharging the vaporsubstantially without oil from the top of the motor housing into a maincondenser, where it is cooled and liquefied for use in the evaporator.

Referencescitednthelectthispatent orthcoriginalpatent UNITEDSTATESPATENTS Greenwald Feb. 21, 1933 Dennedy May 29, 1934 Rataiczak s. May1.3, 1947

